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T h e C o l o r f u l S e e s a w. 12 – April- 2011 The Role of Heavy Fermions in Fundamental Physics. Sogee Spinner University of Wisconsin-Madison. JHEP 1101 (2011) 046: P. Fileviez Perez, T. Han, SS, M. Trenkel. Phys.Rev . D80 (2009) 053006 : P. Fileviez Perez, M. Wise.
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TheColorfulSeesaw • 12 – April- 2011 The Role of Heavy Fermions in Fundamental Physics Sogee Spinner University of Wisconsin-Madison JHEP 1101 (2011) 046: P. Fileviez Perez, T. Han, SS, M. Trenkel Phys.Rev. D80 (2009) 053006 : P. Fileviez Perez, M. Wise
Quest For BSM BSM
BSM is Already Here: • Neutrino Masses: • Can be Dirac or Majorana: • Majorana: new heavy particles: Very exciting for LHC if MX~TeV
Outline • Neutrino Mass Models • TheColorfulSeesaw Fields • TheColorfulSeesaw at the LHC • Conclusion
Outline • Neutrino Mass Models • The Colorful Seesaw Fields • The Colorful Seesaw at the LHC • Conclusion
Majorana Schemes • Generically: violates lepton number: • Possible same-sign dilepton signals • Type I: Fermion • Hard to produce without new interactions Minkowski; Yanagida; Gell-Mann et al.; Glashow; Mohapatra & Senjanovic Keung & Senjanovic; Han & Zhang; Aguila & Aguilar-Saavedra; Atre et al.; Kersten & Smirnov; Fileviez Perez et al. • Type II: Scalar • Producedvia vector bosons • Exciting signals from pair produced Konetschny & Kummer; Cheng & Li; Lazarides et al.; Schechter & Valle; Mohapatra & Senjanovic Fileviez Perez, Han, Huang, Li & Wang; Chun et al.; Garayoa & Schwetz; Akeroyd et al.; Huitu et al. • Type III: Fermion • Fermionic also through Drell-Yan Foot Lew, He & Joshi Franceschini et al; Arhrib, Bajc, Ghosh, Han, Huang, Puljak & Senjanovic; Li & He, Aguila & Aguilar-Saavedra
Radiative Seesaw Zee ‘80 • Zee Model: Scalar and • , LNV not clear • One type of scalar and one type of fermion: Fileviez Perez, Wise ‘09
Choose Colorless Fields Type I Seesaw Fractionally charged Fractionally charged Type III Seesaw
Colorful Fields Type I Seesaw New Fractionally charged Fractionally charged Type III Seesaw New
TheColorfulSeesaw • One massless neutrino • Allows normal hierarchy (NH): • And inverted hierarchy (IH):
TheColorfulSeesaw Neutrino Masses: Loop Function Compare to TeV type I seesaw:
Lepton Number Violation • Lepton number violation (LNV)requires • Lepton flavor violation (LFV) requires Order 1 Yν (Liao & Liu ‘10; Fileviez Perez, SS, Trenkel ‘11) Scanned over neutrino parameters.
Outline • Neutrino Mass Models • TheColorfulSeesawFields • The Colorful Seesaw at the LHC • Conclusion
Scalar Color Octet • So called Manohar-Wise (‘06) • Higgs doublet color adjoint • Couples to quarks just like Higgs • Therefore satisfies minimal flavor violation Ansatz (MFV) • Transforms as Higgs under flavor • Pheno has been studied Gresham & Wise; Fileviez Perez, Gavin, McElmurry &Petriell0; Gerbush et al.;
Scalar Color Octet • Physical states: • Mass split by Higgs interactions: electroweak • Mild coupling to down gives • fieldsfairly degenerate • Decays: • For larger splitting, heavier S decay to W and lighter S, e.g.:
Fermionic Octet • Quantum numbers of gluino (same production) • Decays governed by Yukawa coupling to Leptons • Use Casas-Ibarra (‘01) to relate : • is a complex matrix with • Assumed real, in normal hierarchy:
Fermionic Octet Decays • Or three-body decays • For • Decay length: scan over and mixings. Various decay lengths: Could also be R-hadron.
Decays with Tri-Bimaximal Mixings No Phases • NH: or channels always larger than • NH: and coincide
General Mixing • Scanned over mixing angles and phases • Not as predictive • NH: and channel still larger then
Outline • Neutrino Mass Models • The Colorful Seesaw Fields • TheColorfulSeesaw at the LHC • Conclusion
Signals • LNV: same-sign dileptons • Final states of interests: • Leading background: • One pair of like-sign tops decay semi-leptonically • Still before MET cuts
Number of Events for 10 fb-1: • Scanned over neutrino parameter • Signal > background even before cuts, up to • For 14 TeV, up to • Large particle multiplicity makes reconstruction challenging, but large number of events can make up for it
Conclusion • Neutrino masses might lead to exciting LHC signals • Same-sign dileptons (LNV) with electroweak cross section • ColorfulSeesaw also has same-sign dileptonsbut strong cross sections. • One-loop seesaw mechanism • Scalar color octet, isospin doublet S • Fermionic color octet • More signal events than background up to • With luck, might also discriminate: NH, IH